To extract extra-heavy oil or bitumen from oil sands or oil shale deposits by means of pipeline systems, which are introduced through boreholes, the flowability of the source material present in a solid consistency must be significantly increased. This can be achieved by increasing the temperature of the deposit in the reservoir.
If to this end, an inductive heating element is used exclusively or to assist with the conventional SAGD (Steam Assisted Gravity Drainage) method, the problem occurs whereby adjacent simultaneously energized inductors can mutually negatively influence one another. Adjacent oppositely energized inductors weaken in respect of the heating output deposited in the reservoir.
In the former German patent applications with application numbers 10 2007 008 292.6, 10 2007 036 832.3 and 10 2007 040 605.5, individual inductor pairs, i.e. forward and return conductors, are energized in predetermined geometric configurations in order to inductively heat the reservoir. In this process the current rating is used to set the desired heating output, while the phase position is fixedly set at 180° between adjacent inductors. This out-of-phase energization inevitably results from the operation of an inductor pair with forward and return conductors to a generator. In a parallel patent application by the applicant with the title “Installation for the “in-situ” extraction of a substance containing hydrocarbon”, the control of the heating output distribution in an array of inductors is inter alia described, wherein this is achieved by the ability to set the current amplitudes and the phase position of adjacent inductor pairs. All previous patent applications assume that energization throughout longer periods of days to months only experiences small adjustments and a fixed assignment of a generator to an inductor pair exists.